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Tropical cyclones. Natural Hazards. Where do they form?. Tropical Cyclones are formed over the ocean in the area around the equator, between the Tropic of Cancer and the Tropic of Capricorn. In order for a cyclone to form, the ocean waters need to be warm, at least 26°C. . How do they form?. - PowerPoint PPT Presentation
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Tropical cyclonesNatural Hazards
Where do they form?•Tropical Cyclones are formed over the
ocean in the area around the equator, between the Tropic of Cancer and the Tropic of Capricorn.
•In order for a cyclone to form, the ocean waters need to be warm, at least 26°C.
How do they form?•Above the warm ocean, water evaporates
and form clouds. If there is low air pressure where the clouds are formed, it pulls them in and they begin to rotate.
• It is the Earth’s rotation and spinning on its axis that causes the cyclone’s clouds to rotate. Clouds will continue to form and begin spinning more.
How often do they occur?•Cyclone season in Australia is between
November and April, but cyclones can still occur in the month of May.
•The season for Hurricanes and Typhoons in the Northern Hemisphere is between June and November.
•According to the Bureau of Meteorology, Australia has, on average, 13 cyclones a year. Half of these occur in the western regions.
http://media.smh.com.au/world/century-of-pictures/natures-fury-cyclone-tracy-407879.html
Severity and Categories
The Eye!• The eye is in the centre of the cyclone and can
vary in size, from 10 kilometres to 100 kilometres, depending on the severity of the storm. Do not be fooled by the eye!
• Due to the least amount of air pressure in the eye, it produces clear weather with light wind, no clouds, no rain and some sunshine. But, the storm is not over yet.
• This is only the middle of the storm. Depending on the wind gusts, the eye may pass in a few minutes or in a few hours.
Did you know?• The average life of a cyclone is 1 week.
• After the eye passes, and the other side of the cyclone hits, the wind blows with equal strength but in the opposite direction.
• Tropical Cyclones, from the Southern Hemisphere spin clockwise, and Hurricanes and Typhoons in the Northern Hemisphere spin anti-clockwise.
• Cyclone Tracy was Australia’s most destructive cyclone.
• Cyclones are assigned names, which are picked from a list.
• Cyclone Tracy was a tropical cyclone that devastated the city of Darwin, Northern Territory, Australia, from Christmas Eve to Christmas Day, 1974.
• Category 4 cyclone
• Tracy killed 71 people
• Caused $837 million in damage (1974 AUD)
• Destroyed more than 70 percent of Darwin's buildings, including 80 percent of houses.
Cyclone Tracy
Tracy left homeless more than 41,000 out of the 47,000 inhabitants of the city prior to landfall and required the evacuation of over 30,000 people.
Most of Darwin's population was evacuated to Adelaide, Whyalla, Alice Springs and Sydney, and many never returned to the city.
Bruce Stannard of The Age stated that Cyclone Tracy was a "disaster of the first magnitude ... without parallel in Australia's history.“
Cyclone Tracy
Cyclone Tracy
Tropical Cyclone U
lui, 2010
